Sweet Creek Road Retaining Wall Replacement. Mapleton, OR

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1 Sweet Creek Road Retaining Wall Replacement Mapleton, OR

2 Technical Information Project Completion Date: April 30, 2013 Project Location: Mapleton, OR Size of Project: 15,000 SF, 870 CY Concrete Strength Requirements: (cu. yds., sq. ft., etc.) : The 15 span, 1130 foot bridge, was constructed using 105, four-foot wide by 30 inch thick precast, pre-stressed concrete slabs, varying in length from 50 to 81 feet and totaling 7,902 linear feet. Each span is made up of 7 slabs. The slabs rest on a total of 16 reinforced concrete caps ranging from 3 to 4 foot wide by 4 foot deep. 240 yards of concrete was used for bridge cap construction. Each cap sets on four concrete-filled steel pipe piles drilled 15 feet into bedrock. A total of 64 steel pipe piles support the length of the structure. The 64 pipe piles are encased in a total of 121 yards of concrete. Water/Cement Ratios: : Reinforced Bridge Caps and End Panels: 0.45 (Standard) / 0.35 (Early Strength); Concrete in Bridge Pipe

3 Unique or High Volume Admixtures: Four primary concrete mix designs were used on the project. Admixtures were needed to slow the set time of the concrete for transportation and also to keep the concrete fluid like for placement by pump operation. 1. Drilled Shaft Concrete 2. Exterior Structural Concrete 3. Exterior Structural Concrete 4. Type F Bridge Rail - Slip Form Total LEED points attributed to concrete construction: This project is credited with two LEED points for the respective sections: Water Quantity (6.1) and Water Quality (6.2). Describe unique mix designs: The most unique concrete mix design used on this project was the 5,000 psi Structural High-Early mix used in bent cap construction. Describe placement challenges or unique techniques: Given the immediate proximity of the Siuslaw River, the narrow roadbed and work area, the adjacent steep rock bluffs, and the needs of motorists, this project presented numerous placement challenges which inevitably drove a completely new design.

Sweet Creek Road is located near the community of Mapleton, Oregon, approximately 15 miles east of the Pacific Ocean, and is a vital transportation link between State Route 126 and large tracts of

4 Sweet Creek Road is located near the community of Mapleton, Oregon, approximately 15 miles east of the Pacific Ocean, and is a vital transportation link between State Route 126 and large tracts of public and private forest lands. The road provides the only all-season access route to 68 rural residences. Particular sections of the roadway had been constant maintenance challenges due to settling pavement, sunken grades and failing retaining walls. Maintenance issues were compounded by a 22 foot wide roadway, bordered by a sheer rock bluff and steep banks of the Siuslaw River. In January 2011, one lane of the roadway sunk severely, resulting in a huge crack, leaving the westbound lane impassable.

The Sweet Creek Road Retaining Wall Replacement Project was designed to replace the failing retaining walls as viewed from the adjacent Siuslaw River

5 The Sweet Creek Road Retaining Wall Replacement Project was designed to replace the failing retaining walls as viewed from the adjacent Siuslaw River and rebuild both lanes of the roadway by constructing two tieback retaining walls totaling 900 feet, connected by a 240 foot long pre-stressed bridge.

The contractor could only work during the hours of 8:00 a.m. to 4:00 p.m., Monday through Friday, allowing traffic to pass through the work zone every hour for a period of five minutes.

6 The contractor could only work during the hours of 8:00 a.m. to 4:00 p.m., Monday through Friday, allowing traffic to pass through the work zone every hour for a period of five minutes. Full road closures were permitted during the hours of 8:00 p.m. to 6:00 a.m. as on-site discoveries forced a completely different design and construction approach.

Prior to beginning construction, the contractor presented Lane County with a Value Engineering Plan (VEP) which proposed replacing the deepest sections of the retaining wall with additional bridge

7 Prior to beginning construction, the contractor presented Lane County with a Value Engineering Plan (VEP) which proposed replacing the deepest sections of the retaining wall with additional bridge spans. The contractor had difficulty designing a shoring plan that would allow deep excavations for double tieback retaining wall construction while maintaining traffic flow on half of the existing roadway.

8 The VEP served as the foundation for extensive design changes. It eliminated all double tieback sections of the wall and it changed the project from a single, 240-foot, three-span bridge with two tieback retaining walls into two bridges having a total of 11 spans connected by a 180-foot tieback retaining wall.

9 As soldier piles were being drilled and installed for the remaining retaining walls, a second issue presented itself. In some locations bedrock was being encountered at depths greater than those estimated on the plans. These soldier piles were so deep they would require a double tieback.

10 It was further discovered during the initial drilling for the retaining wall soldier piles, that the rock encountered, which was thought to be bedrock, was actually large boulders. As a result, some soldier piles were installed with inadequate embedment into bedrock.

11 The project team eliminated all but 40 feet of retaining wall and added additional spans which tied the two concrete bridge structures into a single bridge. The result was the construction of one, continuous 15-span concrete bridge structure totaling 1,130 feet.

12 The construction limitations initially imposed by the river, the rock bluff and the narrow and heavily utilized roadway were compounded by differing soil and bedrock conditions discovered during construction.

This project was unique in that it began its life primarily as a retaining wall replacement project, but quickly morphed into a bridge construction

13 This project was unique in that it began its life primarily as a retaining wall replacement project, but quickly morphed into a bridge construction project. In spite of these dramatic changes, the project team through a close partnership was able to retain the project s original scope, schedule and budget.

ARGENTINE CONNECTION BRIDGE TRIPLE TRACK CROSSING. Kansas City Terminal Railway Company

James P. Hyland Page 1 ARGENTINE CONNECTION BRIDGE TRIPLE TRACK CROSSING Kansas City Terminal Railway Company James P. Hyland, P.E. Senior Bridge Engineer TranSystems Corporation James P. Hyland Page 2